哀牢山北段光资源特征初步分析

本文在分析哀牢山北段光资源随海拔和坡向变化特征时发现,与迎风西南坡比较,背风东北坡海拔1000—1900米处有一较强的年日照和太阳总幅射增加的焚风效应带,尤以海拔1500—1600米最明显,这有利于农业生产,但在>1900米处则相对较低。最后,给出日照与雨量的指数关系。

AN ANALYSIS ON LIGHT RESOURCES IN THE NORTHERN PART OF THE AILAO MOUNTAIN

The Ailao Mountain lies in middle Yunnan Province at NNW -SSE direction and is closely perpendicular to the wind regime of southwest monsoon. Thus , the research on the topoclimatic effects is very conspicuous. In this paper,the altitude amd slope distribution characteristics of the light resources in the northern part of Ailao Mountain were discussed according to the sunshine data observed at different altitudes on the northeast and southwest slopes from 1982 to 1986 and in 1986. The findings show that the sunshine is greater in dry season and less in rainy season on the middle to upper slopes,but abundant from January (SW slope) and Febuary(NE slope) to May at the foot, and the total solar radiation is higher in spring,taking 1/3 of the annual total. Compacing with SW slope,the annual sunshine and the total radiation on NE slope are strongly increased at altitudes from 1000-1900m,particularly at 1500-1600m with an increasement of 5% and 400MJ m2,separately. This is advantageous to agriculture. But the sunshine and total radiation is decreased at altitudes >1900m resulting from clouds over the rideg,decreased by 2% and 240MJ m-2,respectively,especially at altitudes of 2200m to 2400m. The mean lapes rate of the sunshine and total radiation is greater on SW slope than on NE slope. Finally,an exponent function relationship between monthly sunshine persent (S1) and rainfall(R) is carried out,i. e,S1=a exp(-bR).